Cognitive-perceptual Factor Research Articles

Clinical Correlates of Schizotypy in Patients With Epilepsy

Clinical correlates of schizotypy were evaluated in 89 adult consecutive outpatients with epilepsy, using the Beck Depression Inventory, the State and Trait Anxiety Inventory, and the Schizotypal Personality Questionnaire (SPQ). Age at onset of the epilepsy significantly correlated with the constricted affect subscale of the SPQ, while a diagnosis of temporal lobe epilepsy correlated with the total SPQ score, the cognitive-perceptual factor of the SPQ, and the suspiciousness subscale of the SPQ. Schizotypal symptoms correlated with early onset of the seizures and a diagnosis of temporal lobe epilepsy, further confirming an association between psychoses and epilepsy.

BIRTH WEIGHT AND MENTAL DISORDER

This study finds that the relatives of schizophrenics have elevated scores on the cognitive-perceptual factor of the schizotypal personality questionnaire (SPQ), particularly for the ‘unusual perceptual experiences’ and ‘ideas of reference’ subscales. These results support recent findings by Kremen et al. (1998) and suggest that previous failures to demonstrate elevated scores on ‘positive’ symptoms of schizotypy may be a function of instrumentation.

Comparison of three computer-administered cognitive tasks as putative endophenotypes of schizophrenia

It has been repeatedly demonstrated that individuals with schizotypal personality features (SPF) exhibit similar endophenotypic traits as persons with schizophrenia. Less research has compared the relative sensitivity of different endophenotypes in the same sample of individuals with SPF. Fourteen university students with SPF (mean age 20.5 ± 1.6; 43% male) and 26 controls (mean age 20.3 ± 1.1; 31% male) were defined by the Abbreviated Schizotypal Personality Questionnaire (SPQ-B). All participants reported no known biological relative with schizophrenia. Participants completed three computer-administered cognitive tasks: a 6-min degraded-stimuli A–X Continuous Performance Test (CPT), the Wisconsin Card Sort Test (WCST), and a Span of Apprehension (SOA) task (6- and 12-letter arrays). On the CPT, only omission errors resulted in a statistically significant group difference, U = 115.5, p = .05, Cohen's d = 0.54 (medium effect size), with the SPF group (mean errors: 3.43 ± 3.28) making more omission errors than controls (mean errors: 1.88 ± 2.66). Notably, 46% of the controls had no omission errors, compared to 14% of the SPF group. The only SPQ-B factor score to show a statistically significant linear relationship with CPT omission errors was the Cognitive–Perceptual factor ( r s = .33, p = .04). Group differences on performance indices from the SOA and WCST did not approach statistical significance. Based on performance from the community-identified schizotypes, results suggest that performance on the CPT may represent a more robust endophenotype of schizophrenia, compared to the SOA and WCST.

Somatosensory Processing and Schizophrenia Liability: Proprioception, Exteroceptive Sensitivity, and Graphesthesia Performance in the Biological Relatives of Schizophrenia Patients.

In the present study, the authors examined somatosensory processing in 30 biological relatives of persons with schizophrenia (hereafter called "schizophrenia relatives"), 30 biological relatives of persons with bipolar affective disorder (psychiatric family control subjects), and 30 healthy control subjects with no family history of psychopathology. All 3 groups completed a weight discrimination task, a 2-point discrimination task, and a complex cognitive somatosensory task (i.e., graphesthesia). The schizophrenia relatives performed significantly worse on all 3 somatosensory tasks compared with both the healthy control subjects and the bipolar relatives. The healthy control subjects and psychiatric family control subjects showed no significant differences on any of the somatosensory tasks. Within the weight discrimination and 2-point discrimination tasks, schizophrenia relatives showed group differences on the d' index, the measure of sensitivity, whereas all 3 groups did not differ on lnbeta, the measure of response bias, suggesting a genuine difference in weight and touch sensitivity. The d' value of the weight discrimination task was significantly associated with both the cognitive-perceptual factor and negative symptom factor of the clinical questionnaire (e.g., Schizotypal Personality Questionnaire; SPQ), whereas the 2-point discrimination d' value and graphesthesia scores were significantly associated only with the cognitive-perceptual factor of the SPQ. Implications for the possible relation between somatosensory task performance and schizophrenia liability are discussed.

Schizotypal Personality Questionnaire-Brief: factor structure and influence of sex and age in a nonclinical population

A growing amount of evidence suggests that schizotypy is a dimensional construct probably consisting of three factors (i.e. cognitive-perceptual, interpersonal, disorganised). This study aimed to ascertain, using a Spanish version of the Schizotypal Personality Questionnaire-Brief (SPQ-B), the factor structure of schizotypy and its relation with sex and age in a nonclinical population. A sample of 443 undergraduate students at the University of Barcelona (Spain) completed the Spanish version of the SPQ-B. Factor analysis resulted in three substantive symptom dimensions: cognitive-perceptual, interpersonal, and disorganised. Age was negatively correlated both with the total score and with the three factors. Analyses of covariance (ANCOVA), entering age as a covariate, revealed sex differences, with higher scores for males in the total score, interpersonal factor, and disorganised factor, and higher scores for females in the cognitive-perceptual factor. The implications of our findings are discussed both regarding sex differences and the influence of age in the expression of schizotypal traits.

Factor structure of neurologic examination abnormalities in unmedicated schizophrenia

The heterogeneity and uncertain significance of neurologic exam abnormalities in schizophrenia prompted us to evaluate their factor structure. We administered a modified version of the Neurological Evaluation Scale (NES) to 103 unmedicated patients with schizophrenia. Data were distilled by combining right- and left-side scores, and by eliminating superfluous, rarely abnormal and unreliable items from the analysis. Exploratory principal components analysis yielded four factors: repetitive motor tasks (fist–ring, fist–edge–palm, alternating fist–palm, dysdiadochokinesis); cognitive–perceptual tasks (memory, audiovisual integration, right–left orientation, face–hand test, rhythm tapping reproduction); balancing tasks (Romberg, tandem gait); and the palmomental reflex. Evaluation of the relationship between these factors and clinical and demographic variables revealed a robust correlation between the cognitive–perceptual factor and full-scale IQ score. This analysis is a step toward developing empirical subscales of a modified NES, which may provide insights into the nature of neurologic impairment in schizophrenia and may prove clinically useful.

Schizotypy in community samples: the three-factor structure and correlation with sustained attention.

The authors examined cross-cultural applicability of the Schizotypal Personality Questionnaire (SPQ), the Perceptual Aberration Scale (PAS), and the Continuous Performance Test in community samples of Taiwanese adults and adolescents. The authors tested hypotheses that a 3-factor structure of the SPQ (Cognitive-Perceptual, Interpersonal, and Disorganization: A. Raine et al., 1994) exists for both samples and that the Interpersonal factor is associated with poorer attention. The authors replicated the 3-factor model for both samples, and they externally validated the model in adults: The Interpersonal factor and possibly the Disorganization factor were associated with poorer attention, whereas the Cognitive-Perceptual factor was not. The PAS differed from the Cognitive-Perceptual factor in its consistent association with poorer attention in both samples. These have important implications for the scales in the early detection of the schizotypy in various cultures.

The factor structure of schizotypal symptoms in a clinical population.

There is some support for the hypothesis that the factor structure of schizophrenia symptoms is similar to the factor structure of schizotypal symptoms in nonschizophrenia populations. However, no studies to date have examined schizotypal symptoms in patients with personality disorders. In this study, confirmatory factor analyses were conducted to test the relative fit of several models of the factorial structure of schizotypal symptoms in patients diagnosed with personality disorders. The EQS: Structural Equations Program was used to analyze DSM-III symptoms of schizotypal personality disorder (SPD) based on structured clinical interviews with 213 patients meeting a diagnosis for at least one personality disorder. A subgroup of the total sample was also evaluated for DSM-III-R criteria (n = 143) to test competing models of the DSM-III-R symptoms of SPD. A three-factor model consisting of a cognitive-perceptual, interpersonal, and paranoid factor yielded the best fit to the data relative to the other models tested. These results suggest that the three-factor model of schizophrenia symptoms may not entirely correspond to the factors underlying milder schizotypal symptoms expressed in a clinical population. It is suggested that future research focus on both the similarities and the differences between SPD and schizophrenia.

Mixed Handedness and Features of Schizotypal Personality in a Nonclinical Sample

Using a nonclinical, noncollege sample, this study set out to confirm and extend previous findings of a relationship between the cognitive-perceptual features of schizotypal personality and mixed handedness using the Schizotypal Personality Questionnaire (SPQ). Based on previous findings of relationships between nondextrality and thought disorder in schizophrenia, it was predicted that the odd speech subscale of the SPQ would have the strongest relationship with mixed handedness. Mixed-handed adults did have significantly higher scores than right-handed and left-handed adults on the cognitive-perceptual factor and its subscale of odd speech. Similar trends were also observed for the cognitive-perceptual subscales of suspiciousness, eccentric behavior, and unusual perceptual experiences. These results support and extend previous findings, and are broadly consistent with the association between thought disorder and nondextrality in schizophrenia.